[vlc-devel] [PATCH 1/1] codec: Add GStreamer based video decoder module

Rafaël Carré funman at videolan.org
Sat Apr 19 11:08:45 CEST 2014


Hello Vikram,

Nice to see that long awaited GStreamer decoder module :)

Now we need a GStreamer module using libvlc and the loop will be complete!

On 04/19/14 10:21, Vikram Fugro wrote:
> This module currently supports h264, mpeg4,
> vp8, mpeg2, flashvideo, wmv1/2/3, vc1 decoder
> plugins provided by GStreamer 1.0 library.
> 
> Signed-off-by: Vikram Fugro <ved.kpl at gmail.com>
> ---
>  configure.ac              |    5 +
>  modules/codec/Makefile.am |    7 +
>  modules/codec/gstcodec.c  |  998 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1010 insertions(+)
>  create mode 100644 modules/codec/gstcodec.c
> 
> diff --git a/configure.ac b/configure.ac

> diff --git a/modules/codec/Makefile.am b/modules/codec/Makefile.am

OK

> diff --git a/modules/codec/gstcodec.c b/modules/codec/gstcodec.c
> new file mode 100644
> index 0000000..43319a7
> --- /dev/null
> +++ b/modules/codec/gstcodec.c
> @@ -0,0 +1,998 @@
> +/*****************************************************************************
> + * gstcodec.c: video decoder module making use of gstreamer
> + *****************************************************************************
> + * Copyright (C) 1999-2014 the VideoLAN team
> + * $Id:
> + *
> + * Author: Vikram Fugro <ved.kpl at gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
> + *****************************************************************************/
> +
> +/*****************************************************************************
> + * Preamble
> + *****************************************************************************/
> +#ifdef HAVE_CONFIG_H
> +# include "config.h"
> +#endif
> +
> +#include <vlc_common.h>
> +#include <vlc_plugin.h>
> +#include <vlc_codec.h>
> +#include <vlc_sout.h>
> +#include <vlc_input.h>
> +
> +#include <assert.h>
> +#include <limits.h>
> +
> +#include <gst/gst.h>
> +#include <gst/video/gstvideometa.h>
> +#include <gst/video/video.h>
> +#include <gst/app/gstappsrc.h>
> +#include <gst/gstatomicqueue.h>
> +
> +struct decoder_sys_t
> +{
> +    GstElement* p_decoder;
> +    GstElement* p_decode_src;
> +    GstElement* p_decode_in;
> +    GstElement* p_decode_out;
> +
> +    GstBus* p_bus;
> +
> +    GstVideoInfo vinfo;
> +    GstAtomicQueue *p_que;
> +    bool b_prerolled;
> +    bool b_running;
> +
> +    bool b_new_segment_pending;
> +    bool b_out_fmt_set;
> +    vlc_sem_t sem_mt;
> +};
> +
> +/*****************************************************************************
> + * Local prototypes
> + *****************************************************************************/
> +static int  OpenDecoder( vlc_object_t * );
> +static void CloseDecoder( vlc_object_t * );
> +static picture_t *DecodeBlock( decoder_t *, block_t ** );
> +
> +#define MODULE_DESCRIPTION N_( "Various video decoders " \
> +        "delivered by the GStreamer library.")
> +
> +#define USEDECODEBIN_TEXT N_("Use DecodeBin")
> +#define USEDECODEBIN_LONGTEXT N_( \
> +    "Let DecodeBin choose the decoder." )
> +
> +vlc_module_begin ()
> +    set_shortname( "GStreamer")
> +    add_shortcut( "gstreamer" )
> +    set_category( CAT_INPUT )
> +    set_subcategory( SUBCAT_INPUT_VCODEC )
> +    /* decoder main module */
> +    set_description( N_( "GStreamer video decoder" ) )
> +    set_help( MODULE_DESCRIPTION )
> +    set_capability( "decoder", 50 )
> +    set_section( N_( "Decoding" ) , NULL )
> +    set_callbacks( OpenDecoder, CloseDecoder )
> +    add_bool( "use-decodebin", false, USEDECODEBIN_TEXT,
> +        USEDECODEBIN_LONGTEXT, false)
> +vlc_module_end ()
> +
> +static vlc_fourcc_t gst_to_vlc_fmt( const gchar* psz_fmt )
> +{
> +    if ( !psz_fmt )
> +        return 0;
> +
> +    if( !strcmp ( psz_fmt, "I420" ) )
> +        return VLC_CODEC_I420;
> +    if( !strcmp ( psz_fmt, "YV12" ) )
> +        return VLC_CODEC_YV12;
> +    if( !strcmp ( psz_fmt, "YUY2" ) ||
> +            !strcmp ( psz_fmt, "YUYV" ) )
> +        return VLC_CODEC_YUYV;
> +    if( !strcmp ( psz_fmt, "UYVY" ) )
> +        return VLC_CODEC_UYVY;
> +    if( !strcmp ( psz_fmt, "VYUY" ) )
> +        return VLC_CODEC_VYUY;
> +    if( !strcmp ( psz_fmt, "NV12" ) )
> +        return VLC_CODEC_NV12;
> +    if( !strcmp ( psz_fmt, "NV21" ) )
> +        return VLC_CODEC_NV21;
> +
> +    return 0;
> +}
> +
> +static GstStructure* vlc_to_gst_fmt( vlc_fourcc_t i_fmt )
> +{
> +    GstStructure* p_str = NULL;
> +
> +    switch( i_fmt )
> +    {
> +        case VLC_CODEC_H264:

nitpicking: align case on the switch level

> +            p_str = gst_structure_new_empty( "video/x-h264" );
> +            gst_structure_set( p_str, "alignment", G_TYPE_STRING, "au", NULL );
> +            break;
> +        case VLC_CODEC_MP4V:
> +            p_str = gst_structure_new_empty( "video/mpeg" );
> +            gst_structure_set( p_str, "mpegversion", G_TYPE_INT, 4,
> +                    "systemstream", G_TYPE_BOOLEAN, FALSE, NULL );
> +            break;
> +        case VLC_CODEC_VP8:
> +            p_str = gst_structure_new_empty( "video/x-vp8" );
> +            break;
> +        case VLC_CODEC_MPGV:
> +            p_str = gst_structure_new_empty( "video/mpeg" );
> +            gst_structure_set( p_str, "mpegversion", G_TYPE_INT, 2,
> +                    "systemstream", G_TYPE_BOOLEAN, FALSE, NULL );
> +            break;
> +        case VLC_CODEC_FLV1:
> +            p_str = gst_structure_new_empty( "video/x-flash-video" );
> +            gst_structure_set( p_str, "flvversion", G_TYPE_INT, 1, NULL );
> +            break;
> +        case VLC_CODEC_WMV1:
> +            p_str = gst_structure_new_empty( "video/x-wmv" );
> +            gst_structure_set( p_str, "wmvversion", G_TYPE_INT, 1,
> +                "format", G_TYPE_STRING, "WMV1", NULL );
> +            break;
> +        case VLC_CODEC_WMV2:
> +            p_str = gst_structure_new_empty( "video/x-wmv" );
> +            gst_structure_set( p_str, "wmvversion", G_TYPE_INT, 2,
> +                "format", G_TYPE_STRING, "WMV2", NULL );
> +            break;
> +        case VLC_CODEC_WMV3:
> +            p_str = gst_structure_new_empty( "video/x-wmv" );
> +            gst_structure_set( p_str, "wmvversion", G_TYPE_INT, 3,
> +                "format", G_TYPE_STRING, "WMV3", NULL );
> +            break;
> +        case VLC_CODEC_VC1:
> +            p_str = gst_structure_new_empty( "video/x-wmv" );
> +            gst_structure_set( p_str, "wmvversion", G_TYPE_INT, 3,
> +                "format", G_TYPE_STRING, "WVC1", NULL );
> +            break;
> +        default:
> +            break;
> +    }
> +
> +    return p_str;
> +}
> +
> +/* Probe for the buffer just pushed into appsrc
> + * Maintains sync between the DecodeBlock() and
> + * the appsrc */
> +static GstPadProbeReturn buffer_probe_cb( GstPad* p_pad,
> +        GstPadProbeInfo* p_info, gpointer p_data )
> +{
> +    decoder_t* p_dec = ( decoder_t* )p_data;
> +    vlc_sem_post( &p_dec->p_sys->sem_mt );
> +    return GST_PAD_PROBE_OK;
> +}
> +
> +/* Emitted by appsrc when serving a seek request.
> + * Seek over here is only used for flushing the buffers.
> + * Returns TRUE always, as the 'real' seek will be
> + * done by VLC framework */
> +static gboolean seek_data_cb( GstAppSrc* p_src, guint64 l_offset,
> +        gpointer p_data )
> +{
> +    decoder_t* p_dec = ( decoder_t* )p_data;
> +    msg_Dbg( p_dec, "appsrc seeking to %llu", (unsigned long long)l_offset );
> +    return TRUE;
> +}
> +
> +/* Emitted by decodebin when there are no more
> + * outputs. In this case it will be mostly and
> + * should be one */
> +static void no_more_pads_cb( GstElement* p_ele, gpointer p_data )
> +{
> +    decoder_t* p_dec = ( decoder_t* )p_data;
> +    GstPad* p_pad;
> +
> +    msg_Dbg( p_dec, "no more pads" );
> +
> +    p_pad = gst_element_get_static_pad( p_dec->p_sys->p_decode_out,

You could declare p_sys = p_dec->p_sys and use p_sys instead, that'd make
the code a bit shorter :)

> +            "sink" );
> +    if( p_pad == NULL || !gst_pad_is_linked( p_pad ) )
> +    {
> +        gst_element_post_message ( GST_ELEMENT( p_dec->p_sys->p_decoder ),
> +                gst_message_new_application( GST_OBJECT(
> +                        p_dec->p_sys->p_decoder ),
> +                    gst_structure_new( "VlcGstError",
> +                        "message", G_TYPE_STRING,
> +                        "failed to link decode out pad",
> +                        NULL ) ) );
> +    }
> +
> +    gst_object_unref( p_pad );

Is gst_object_unref(NULL) allowed?

> +}
> +
> +/* Emitted by decodebin and links decodebin to fakesink*/
> +static void pad_added_cb( GstElement* p_ele, GstPad* p_pad, gpointer p_data )
> +{
> +    decoder_t* p_dec = ( decoder_t* )p_data;
> +    GstPad* p_sinkpad;
> +
> +    p_sinkpad = gst_element_get_static_pad(
> +            p_dec->p_sys->p_decode_out, "sink" );
> +
> +    if( !gst_pad_is_linked( p_sinkpad ) )
> +    {
> +        GstCaps* p_caps;
> +
> +        /* Get the output format type */
> +        p_caps = gst_pad_get_current_caps( p_pad );
> +        if( p_caps )
> +        {
> +            GstStructure* p_str;
> +
> +            p_str = gst_caps_get_structure( p_caps, 0 );
> +
> +            /* We want raw caps only */
> +            if( gst_structure_has_name( p_str, "video/x-raw" ) ) {
> +                if( !gst_video_info_from_caps( &p_dec->p_sys->vinfo,
> +                            p_caps ) )
> +                {
> +                    gst_element_post_message(
> +                            GST_ELEMENT( p_dec->p_sys->p_decoder ),
> +                            gst_message_new_application( GST_OBJECT(
> +                                    p_dec->p_sys->p_decoder ),
> +                                gst_structure_new( "VlcGstWarning",
> +                                    "message", G_TYPE_STRING,
> +                                    "failed to get video info from caps",
> +                                    NULL ) ) );
> +                } else
> +                    gst_pad_link( p_pad, p_sinkpad );
> +            }
> +
> +            gst_caps_unref( p_caps );
> +        }
> +    }
> +
> +    gst_object_unref( p_sinkpad );
> +}
> +
> +/* Emitted by fakesink for every buffer and sets the
> + * output format in VLC context for vout. Adds the
> + * buffer to the queue */
> +static void frame_handoff_cb( GstElement* p_ele, GstBuffer* p_buf,
> +        GstPad* p_pad, gpointer p_data )
> +{
> +    decoder_t* p_dec = ( decoder_t* )p_data;
> +here
> +    if( unlikely( p_dec->p_sys->b_out_fmt_set == false ) )
> +    {
> +        do
> +        {
> +            if( gst_pad_has_current_caps( p_pad ) )

while (gst_pad_has_current_caps(p_pad))

> +            {
> +                GstCaps* p_caps;
> +
> +                p_caps = gst_pad_get_current_caps( p_pad );
> +                if( p_caps )

if (!p_caps) break;

> +                {
> +                    GstStructure* p_str;
> +
> +                    p_str = gst_caps_get_structure( p_caps, 0 );
> +                    if( p_str && gst_structure_has_name( p_str, "video/x-raw" ) )
> +                    {
> +                        gboolean b_ret = FALSE;
> +
> +                        if( !gst_video_info_from_caps( &p_dec->p_sys->vinfo,
> +                                    p_caps ) )
> +                        {
> +                            gst_element_post_message(
> +                                    GST_ELEMENT( p_dec->p_sys->p_decoder ),
> +                                    gst_message_new_application( GST_OBJECT(
> +                                            p_dec->p_sys->p_decoder ),
> +                                        gst_structure_new( "VlcGstWarning",
> +                                            "message", G_TYPE_STRING,
> +                                            "failed to get video info from caps",
> +                                            NULL ) ) );
> +                            gst_caps_unref( p_caps );
> +                            break;
> +                        }
> +                        else
> +                        {
> +                            p_dec->fmt_out.i_codec = gst_to_vlc_fmt(
> +                                    gst_structure_get_string ( p_str, "format" ) );
> +
> +                            if( !p_dec->fmt_out.i_codec )
> +                            {
> +                                gst_element_post_message(
> +                                        GST_ELEMENT( p_dec->p_sys->p_decoder ),
> +                                        gst_message_new_application( GST_OBJECT(
> +                                                p_dec->p_sys->p_decoder ),
> +                                            gst_structure_new( "VlcGstWarning",
> +                                                "message", G_TYPE_STRING,
> +                                                "invalid output format",
> +                                                NULL ) ) );
> +                                gst_caps_unref( p_caps );
> +                                break;
> +                            }
> +
> +                            b_ret = gst_structure_get_fraction( p_str,
> +                                    "pixel-aspect-ratio",
> +                                    ( gint* )&p_dec->fmt_out.video.i_sar_num,
> +                                    ( gint* )&p_dec->fmt_out.video.i_sar_den );
> +
> +                            if( !b_ret || !p_dec->fmt_out.video.i_sar_num ||
> +                                    !p_dec->fmt_out.video.i_sar_den )
> +                            {
> +                                p_dec->fmt_out.video.i_sar_num = 1;
> +                                p_dec->fmt_out.video.i_sar_den = 1;
> +                            }
> +
> +                            b_ret = gst_structure_get_int ( p_str, "width",
> +                                    ( gint* )&p_dec->fmt_out.video.i_width );
> +                            b_ret &= gst_structure_get_int ( p_str, "height",
> +                                    ( gint* )&p_dec->fmt_out.video.i_height );

I'd prefer to use && here

> +
> +                            if( !b_ret || !p_dec->fmt_out.video.i_width ||
> +                                    !p_dec->fmt_out.video.i_height )
> +                            {
> +                                p_dec->fmt_out.video.i_width =
> +                                    p_dec->fmt_in.video.i_width;
> +                                p_dec->fmt_out.video.i_height =
> +                                    p_dec->fmt_in.video.i_height;
> +                            }
> +
> +                            b_ret = gst_structure_get_fraction ( p_str, "framerate",
> +                                    ( gint* )&p_dec->fmt_out.video.i_frame_rate,
> +                                    ( gint* )&p_dec->fmt_out.video.i_frame_rate_base
> +                                    );
> +
> +                            if( !b_ret || !p_dec->fmt_out.video.i_frame_rate ||
> +                                    !p_dec->fmt_out.video.i_frame_rate_base )
> +                            {
> +                                p_dec->fmt_out.video.i_frame_rate =
> +                                    p_dec->fmt_in.video.i_frame_rate;
> +                                p_dec->fmt_out.video.i_frame_rate_base =
> +                                    p_dec->fmt_in.video.i_frame_rate_base;
> +                            }
> +                        }
> +                    }
> +                    gst_caps_unref( p_caps );
> +                    p_dec->p_sys->b_out_fmt_set = true;
> +                }
> +            }
> +        } while( 0 );
> +
> +        if( !p_dec->p_sys->b_out_fmt_set )
> +            return;
> +    }
> +
> +    /* Push the buffer to the queue */
> +    gst_atomic_queue_push( p_dec->p_sys->p_que, gst_buffer_ref( p_buf ) );
> +}
> +
> +/* Copy the frame data from the GstBuffer (from decoder)
> + * to the picture obtained from downstream in VLC */
> +static void gst_CopyPicture( picture_t *p_pic, GstVideoFrame *frame )

So it's not possible to tell Gst where to decode data and let it do
the memcpy if e.g. using a hardware decoder?

> +{
> +    int i_plane, i_planes, i_line, i_dst_stride, i_src_stride;
> +    uint8_t *p_dst, *p_src;
> +    int i_w, i_h;
> +
> +    i_planes = p_pic->i_planes < 3 ? p_pic->i_planes : 3;
> +    for( i_plane = 0; i_plane < i_planes; i_plane++ )
> +    {
> +        p_dst = p_pic->p[i_plane].p_pixels;
> +        p_src = GST_VIDEO_FRAME_PLANE_DATA( frame, i_plane );
> +        i_dst_stride  = p_pic->p[i_plane].i_pitch;
> +        i_src_stride  = GST_VIDEO_FRAME_PLANE_STRIDE( frame, i_plane );
> +
> +        i_w = GST_VIDEO_FRAME_COMP_WIDTH( frame,
> +                i_plane ) * GST_VIDEO_FRAME_COMP_PSTRIDE( frame, i_plane );
> +        i_h = GST_VIDEO_FRAME_COMP_HEIGHT( frame, i_plane );
> +
> +        for( i_line = 0;
> +                i_line < __MIN( p_pic->p[i_plane].i_lines, i_h );
> +                i_line++ )
> +        {
> +            memcpy( p_dst, p_src, i_w );
> +            p_src += i_src_stride;
> +            p_dst += i_dst_stride;
> +        }
> +    }
> +}
> +
> +/* Check if the element can use this caps */
> +static gint find_decoder_func( gconstpointer p_p1, gconstpointer p_p2 )
> +{
> +    GstElementFactory *p_factory;
> +    GstCaps* p_caps;
> +
> +    p_factory = ( GstElementFactory* )p_p1;
> +    p_caps = ( GstCaps * )p_p2;
> +
> +    return( !gst_element_factory_can_sink_any_caps( p_factory, p_caps ) );
> +}
> +
> +static gint compare_ranks_func( gconstpointer p_p1, gconstpointer p_p2 )

Use gst_plugin_feature_rank_compare_func directly instead of this wrapper

> +{
> +    return gst_plugin_feature_rank_compare_func( p_p1, p_p2 );
> +}
> +
> +/*****************************************************************************
> + * OpenDecoder: probe the decoder and return score
> + *****************************************************************************/
> +static int OpenDecoder( vlc_object_t *p_this )
> +{
> +    decoder_t *p_dec = ( decoder_t* )p_this;
> +    decoder_sys_t *p_sys;
> +    GstStateChangeReturn i_ret;
> +    gboolean b_ret;
> +    GstPad* p_pad;
> +    GstCaps* p_caps = NULL;
> +    GstStructure* p_str = NULL;
> +    GstAppSrcCallbacks cb;
> +    guint8* p_data = NULL;
> +    int i_rval = VLC_SUCCESS;
> +    GList* p_list = NULL;
> +    bool dbin;
> +#define VLC_GST_CHECK(r, v, s, t, x) \
> +    { if(r == v) { msg_Info(p_dec, s); i_rval = t; goto x; } }

msg_Err ?

> +
> +    gst_init (NULL, NULL);
> +
> +    p_str = vlc_to_gst_fmt( p_dec->fmt_in.i_codec );
> +    if( !p_str ) {
> +        return VLC_EGENERIC;
> +    }
> +
> +    /* Allocate the memory needed to store the decoder's structure */
> +    if( ( p_dec->p_sys = p_sys = calloc( 1, sizeof( *p_sys ) ) ) == NULL )
> +        return VLC_ENOMEM;
> +
> +    /* Set callbacks */
> +    p_dec->pf_decode_video = ( picture_t*( * )( decoder_t*, block_t** ) )
> +        DecodeBlock;

Only set this callback when decoder opened successfully

> +
> +    dbin = var_CreateGetBool( p_dec, "use-decodebin" );
> +    msg_Info( p_dec, "Using decodebin? %s", dbin ? "yes ":"no" );
> +
> +    /* Force packetized for now */
> +    p_dec->b_need_packetized = true;
> +
> +    if( p_dec->fmt_in.video.i_width &&
> +            p_dec->fmt_in.video.i_height )
> +    {
> +        gst_structure_set( p_str,
> +                "width", G_TYPE_INT, p_dec->fmt_in.video.i_width,
> +                "height", G_TYPE_INT, p_dec->fmt_in.video.i_height, NULL );
> +    }
> +
> +    if( p_dec->fmt_in.video.i_frame_rate &&
> +            p_dec->fmt_in.video.i_frame_rate_base )
> +    {
> +        gst_structure_set( p_str, "framerate", GST_TYPE_FRACTION,
> +                p_dec->fmt_in.video.i_frame_rate,
> +                p_dec->fmt_in.video.i_frame_rate_base, NULL );
> +    }
> +
> +    if( p_dec->fmt_in.video.i_sar_num &&
> +            p_dec->fmt_in.video.i_sar_den )
> +    {
> +        gst_structure_set( p_str, "pixel-aspect-ratio", GST_TYPE_FRACTION,
> +                p_dec->fmt_in.video.i_sar_num,
> +                p_dec->fmt_in.video.i_sar_den, NULL );
> +    }
> +
> +    if( p_dec->fmt_in.i_extra )
> +    {
> +        GstBuffer* p_buf;
> +
> +        p_data = malloc( p_dec->fmt_in.i_extra );

g_malloc() ?

> +        VLC_GST_CHECK( p_data, NULL, "failed to create codec data buffer",
> +                VLC_ENOMEM, fail );
> +        memcpy( p_data, p_dec->fmt_in.p_extra, p_dec->fmt_in.i_extra );
> +        p_buf = gst_buffer_new_wrapped( p_data, p_dec->fmt_in.i_extra );
> +        VLC_GST_CHECK( p_buf, NULL, "failed to create codec data gstbuffer",
> +                VLC_ENOMEM, fail );
> +
> +        gst_structure_set( p_str, "codec_data", GST_TYPE_BUFFER, p_buf, NULL );
> +        gst_buffer_unref( p_buf );
> +        p_data = NULL;
> +    }
> +
> +    p_caps = gst_caps_new_empty( );
> +    gst_caps_append_structure( p_caps, p_str );
> +    p_str = NULL;
> +
> +    /* Get the list of all the available gstreamer decoders */
> +    p_list = gst_element_factory_list_get_elements(
> +            GST_ELEMENT_FACTORY_TYPE_DECODER, GST_RANK_MARGINAL );
> +    VLC_GST_CHECK( p_list, NULL, "no decoder list found", VLC_ENOMOD, fail );
> +    if( !dbin )
> +    {
> +        GList* p_l;
> +        /* Sort them as per ranks */
> +        p_list = g_list_sort( p_list, compare_ranks_func );
> +        VLC_GST_CHECK( p_list, NULL, "failed to sort decoders list",
> +                VLC_ENOMOD, fail );
> +        p_l = g_list_find_custom( p_list, p_caps, find_decoder_func );
> +        VLC_GST_CHECK( p_l, NULL, "no suitable decoder found",
> +                VLC_ENOMOD, fail );
> +        /* create the decoder with highest rank */
> +        p_sys->p_decode_in = gst_element_factory_create(
> +                (GstElementFactory*)p_l->data, NULL );
> +        VLC_GST_CHECK( p_sys->p_decode_in, NULL,
> +                "failed to create decoder", VLC_ENOMOD, fail );
> +    }
> +    else
> +    {
> +        GList* p_l;
> +        /* Just check if any suitable decoder exists, rest will be
> +         * handled by decodebin */
> +        p_l = g_list_find_custom( p_list, p_caps, find_decoder_func );
> +        VLC_GST_CHECK( p_l, NULL, "no suitable decoder found",
> +                VLC_ENOMOD, fail );
> +    }
> +    gst_plugin_feature_list_free( p_list );
> +    p_list = NULL;
> +
> +    vlc_sem_init( &p_sys->sem_mt, 0 );
> +    p_dec->fmt_out.i_cat = VIDEO_ES;
> +
> +    p_sys->b_prerolled = false;
> +    p_sys->b_running = false;
> +    p_sys->b_out_fmt_set = false;
> +
> +    /* Queue: GStreamer thread will dump buffers into this queue,
> +     * DecodeBlock() will pop out the buffers from the queue */
> +    p_sys->p_que = gst_atomic_queue_new( 0 );
> +    VLC_GST_CHECK ( p_sys->p_que, NULL, "failed to create queue",
> +            VLC_ENOMEM, fail );
> +
> +    p_sys->p_decode_src = gst_element_factory_make( "appsrc", NULL );
> +    VLC_GST_CHECK( p_sys->p_decode_src, NULL, "appsrc not found",
> +            VLC_ENOMOD, fail );
> +    g_object_set( G_OBJECT( p_sys->p_decode_src ), "caps", p_caps,
> +            "block", FALSE, "emit-signals", TRUE, "format", GST_FORMAT_BYTES,
> +            "stream-type", GST_APP_STREAM_TYPE_SEEKABLE, NULL );
> +    gst_caps_unref( p_caps );
> +    p_caps = NULL;
> +    cb.enough_data = cb.need_data = NULL;
> +    cb.seek_data = seek_data_cb;
> +    gst_app_src_set_callbacks( GST_APP_SRC( p_sys->p_decode_src ),
> +            &cb, p_dec, NULL );
> +
> +    if( dbin )
> +    {
> +        p_sys->p_decode_in = gst_element_factory_make( "decodebin", NULL );
> +        VLC_GST_CHECK( p_sys->p_decode_in, NULL, "decodebin not found",
> +                VLC_ENOMOD, fail );
> +        //g_object_set( G_OBJECT (p_sys->p_decode_in),
> +        //"max-size-buffers", 2, NULL );
> +        g_signal_connect( G_OBJECT( p_sys->p_decode_in ), "pad-added",
> +                G_CALLBACK( pad_added_cb ), p_dec );
> +        g_signal_connect (G_OBJECT( p_sys->p_decode_in ), "no-more-pads",
> +                G_CALLBACK( no_more_pads_cb ), p_dec );
> +    }
> +    p_pad = gst_element_get_static_pad( p_sys->p_decode_in, "sink" );
> +    VLC_GST_CHECK( p_pad, NULL, "failed to get decoder's sinkpad",
> +            VLC_ENOOBJ, fail );
> +    gst_pad_add_probe( p_pad, GST_PAD_PROBE_TYPE_BUFFER, buffer_probe_cb,
> +            p_dec, NULL );
> +    gst_object_unref( p_pad );
> +
> +    /* fakesink: will emit signal for every available buffer */
> +    p_sys->p_decode_out = gst_element_factory_make( "fakesink", NULL );
> +    VLC_GST_CHECK( p_sys->p_decode_out, NULL, "fakesink not found",
> +            VLC_ENOMOD, fail );
> +    /* connect to the signal with the callback */
> +    g_object_set( G_OBJECT( p_sys->p_decode_out ), "sync", FALSE,
> +            "enable-last-sample", FALSE, "signal-handoffs", TRUE, NULL );
> +    g_signal_connect( G_OBJECT( p_sys->p_decode_out ), "handoff",
> +            G_CALLBACK( frame_handoff_cb ), p_dec );
> +
> +    p_sys->p_decoder = GST_ELEMENT( gst_bin_new( "decoder" ) );
> +    VLC_GST_CHECK( p_sys->p_decoder, NULL, "bin not found", VLC_ENOMOD, fail );
> +    p_sys->p_bus = gst_bus_new( );
> +    VLC_GST_CHECK( p_sys->p_bus, NULL, "failed to create bus",
> +            VLC_ENOMOD, fail );
> +    gst_element_set_bus( p_sys->p_decoder, p_sys->p_bus );
> +
> +    gst_bin_add_many( GST_BIN( p_sys->p_decoder ),
> +            p_sys->p_decode_src, p_sys->p_decode_in,
> +            p_sys->p_decode_out, NULL );
> +    gst_object_ref( p_sys->p_decode_src );
> +    gst_object_ref( p_sys->p_decode_in );
> +    gst_object_ref( p_sys->p_decode_out );
> +
> +    b_ret = gst_element_link( p_sys->p_decode_src, p_sys->p_decode_in );
> +    VLC_GST_CHECK ( b_ret, FALSE, "failed to link src <-> in",
> +            VLC_EGENERIC, fail );
> +
> +    if( !dbin )
> +    {
> +        b_ret = gst_element_link( p_sys->p_decode_in, p_sys->p_decode_out );
> +        VLC_GST_CHECK (b_ret, FALSE, "failed to link in <-> out",
> +                VLC_EGENERIC, fail);
> +    }
> +
> +    /* set the pipeline to playing */
> +    i_ret = gst_element_set_state( p_sys->p_decoder, GST_STATE_PLAYING );
> +    VLC_GST_CHECK( i_ret, GST_STATE_CHANGE_FAILURE,
> +            "set state failure", VLC_EGENERIC, fail );
> +
> +    p_sys->b_running = true;
> +    p_sys->b_new_segment_pending = false;
> +
> +    return VLC_SUCCESS;
> +
> +fail:
> +    if( p_data )
> +        free( p_data );
> +    if( p_caps )
> +    {
> +        gst_caps_unref( p_caps );
> +        p_str = NULL;
> +    }
> +    if( p_str )
> +        gst_structure_free( p_str );
> +    if( p_list )
> +        gst_plugin_feature_list_free( p_list );
> +    CloseDecoder( ( vlc_object_t* )p_dec );
> +    return i_rval;
> +}
> +
> +/* Decode */
> +static picture_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
> +{
> +    block_t *p_block = NULL;
> +    picture_t *p_pic = NULL;
> +    decoder_sys_t *p_sys = p_dec->p_sys;
> +    GstMessage* p_msg;
> +    gboolean b_ret;
> +    guint8* p_data;
> +    GstBuffer* p_buf;
> +
> +    if( !pp_block || !*pp_block ) {
> +        return NULL;
> +    }

Decoder should be flushed if *pp_block == NULL

> +
> +    p_block = *pp_block;
> +
> +    if( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
> +    {
> +        if ( p_block->i_flags & BLOCK_FLAG_DISCONTINUITY )
> +            p_sys->b_new_segment_pending = true;
> +
> +        block_Release( p_block );
> +        return NULL;
> +    }
> +
> +    if ( !p_block->i_buffer )
> +    {
> +        block_Release( p_block );
> +        return NULL;
> +    }
> +
> +    p_data = malloc (p_block->i_buffer);
> +    if( unlikely( p_data == NULL ) )
> +    {
> +        block_Release( p_block );
> +        msg_Err( p_dec, "failed to create buffer" );
> +        p_dec->b_error = true;
> +        goto done;
> +    }
> +    memcpy( p_data, p_block->p_buffer, p_block->i_buffer );
> +    p_buf = gst_buffer_new_wrapped( p_data, p_block->i_buffer );

gst_buffer_new_wrapped_full instead of malloc+memcpy ?

Then you can call block_Release in the destructor

> +    if( unlikely( p_buf == NULL ) )
> +    {
> +        free( p_data );
> +        block_Release( p_block );
> +        msg_Err( p_dec, "failed to create gstbuffer" );
> +        p_dec->b_error = true;
> +        goto done;
> +    }
> +
> +    if( p_block->i_dts > VLC_TS_INVALID )
> +        GST_BUFFER_DTS( p_buf ) = gst_util_uint64_scale( p_block->i_dts,
> +                GST_SECOND, GST_MSECOND );
> +
> +    if( p_block->i_pts <= VLC_TS_INVALID )
> +        GST_BUFFER_PTS( p_buf ) = GST_BUFFER_DTS( p_buf );
> +    else
> +        GST_BUFFER_PTS( p_buf ) = gst_util_uint64_scale( p_block->i_pts,
> +                GST_SECOND, GST_MSECOND );
> +
> +    if( p_dec->fmt_in.video.i_frame_rate  &&
> +            p_dec->fmt_in.video.i_frame_rate_base )
> +        GST_BUFFER_DURATION( p_buf ) = gst_util_uint64_scale( GST_SECOND,
> +                p_dec->fmt_in.video.i_frame_rate_base,
> +                p_dec->fmt_in.video.i_frame_rate );

p_block->i_length ?

> +
> +    /* Send a new segment event, seeking position is
> +     * irrelavant here, as the main motive for a seek
> +     * here, is to tell the elements to start flushing
> +     * and start accepting buffers from a new time segment */
> +    if( unlikely( p_sys->b_new_segment_pending ) )
> +    {
> +        GstBuffer* p_buffer;
> +
> +        b_ret = gst_element_seek_simple( p_sys->p_decoder,
> +                GST_FORMAT_BYTES, GST_SEEK_FLAG_FLUSH, 0 );
> +        msg_Dbg( p_dec, "new segment event : %d", b_ret );
> +
> +        /* flush the ouyput buffers from the queue */
> +        while( ( p_buffer = gst_atomic_queue_pop( p_sys->p_que ) ) )
> +            gst_buffer_unref ( p_buffer );
> +
> +        p_sys->b_new_segment_pending = false;
> +        p_sys->b_prerolled = false;
> +    }
> +
> +    /* Give the input buffer to GStreamer Bin.
> +     *
> +     *  libvlc                     libvlc
> +     *    \ (i/p)              (o/p) ^
> +     *     \                        /
> +     *   ___v____GSTREAMER BIN_____/____
> +     *  |                               |
> +     *  |   appsrc-->decode-->fakesink  |
> +     *  |_______________________________|
> +     *
> +     * * * * * * * * * * * * * * * * * * * * */
> +    if( unlikely( gst_app_src_push_buffer(
> +                    GST_APP_SRC_CAST( p_sys->p_decode_src ), p_buf )
> +                != GST_FLOW_OK ) )
> +    {
> +        p_dec->b_error = true;
> +        msg_Err( p_dec, "failed to push buffer" );
> +        goto done;
> +    }
> +    else
> +    {
> +        vlc_sem_wait( &p_sys->sem_mt );
> +    }
> +
> +    do
> +    {

Remove that do and use goto done instead of break

> +        /* Poll for any messages, errors */
> +        p_msg = gst_bus_pop_filtered( p_sys->p_bus,
> +                GST_MESSAGE_ASYNC_DONE | GST_MESSAGE_ERROR |
> +                GST_MESSAGE_EOS | GST_MESSAGE_APPLICATION |
> +                GST_MESSAGE_WARNING | GST_MESSAGE_INFO );
> +        if( p_msg )
> +        {
> +            switch ( GST_MESSAGE_TYPE( p_msg ) )
> +            {
> +                case GST_MESSAGE_ERROR:
> +                    {
> +                        gchar  *psz_debug;
> +                        GError *p_error;
> +
> +                        gst_message_parse_error (p_msg, &p_error, &psz_debug);
> +                        g_free (psz_debug);
> +
> +                        msg_Err( p_dec, "Error from %s: %s",
> +                                GST_ELEMENT_NAME( GST_MESSAGE_SRC( p_msg ) ),
> +                                p_error->message );
> +                        g_error_free( p_error );
> +                        p_dec->b_error = true;
> +                    }
> +                    break;
> +                case GST_MESSAGE_EOS:
> +                    msg_Warn( p_dec, "got unexpected eos" );
> +                    break;
> +                /* First buffer received */
> +                case GST_MESSAGE_ASYNC_DONE:
> +                    p_sys->b_prerolled = true;
> +                    msg_Dbg( p_dec, "Pipeline is prerolled" );
> +                    break;
> +                case GST_MESSAGE_APPLICATION:
> +                    {
> +                        const GstStructure *p_str;
> +                        gboolean b_err, b_warn;
> +
> +                        p_str = gst_message_get_structure ( p_msg );
> +                        if( p_str &&
> +                                ( (
> +                                   b_err = gst_structure_has_name(
> +                                       p_str,
> +                                       "VlcGstError"
> +                                       )
> +                                  ) ||
> +                                  (
> +                                   b_warn = gst_structure_has_name(
> +                                       p_str,
> +                                       "VlcGstWarning"
> +                                       )
> +                                  ) ) )
> +                        {
> +                            const gchar* psz_str;
> +
> +                            psz_str = gst_structure_get_string( p_str,
> +                                    "message" );
> +
> +                            if( b_err )
> +                            {
> +                                msg_Err( p_dec, psz_str );
> +                                p_dec->b_error = true;
> +                            }
> +                            else if( b_warn )
> +                                msg_Warn( p_dec, psz_str );
> +                        }
> +                    }
> +                    break;
> +                case GST_MESSAGE_INFO:
> +                    {
> +                        gchar  *psz_debug;
> +                        GError *p_error;
> +
> +                        gst_message_parse_info( p_msg, &p_error, &psz_debug );
> +                        g_free( psz_debug );
> +
> +                        msg_Info( p_dec, "Info from %s: %s",
> +                                GST_ELEMENT_NAME( GST_MESSAGE_SRC( p_msg ) ),
> +                                p_error->message );
> +                        g_error_free( p_error );
> +                    }
> +                    break;
> +                case GST_MESSAGE_WARNING:
> +                    {
> +                        gchar  *psz_debug;
> +                        GError *p_error;
> +
> +                        gst_message_parse_info( p_msg, &p_error, &psz_debug );
> +                        g_free( psz_debug );
> +
> +                        msg_Warn( p_dec, "Warning from %s: %s",
> +                                GST_ELEMENT_NAME( GST_MESSAGE_SRC( p_msg ) ),
> +                                p_error->message );
> +                        g_error_free( p_error );
> +                    }
> +                    break;
> +                default:
> +                    break;
> +            }
> +            gst_message_unref( p_msg );
> +        }
> +
> +        /* Look for any output buffers in the queue */
> +        if( gst_atomic_queue_peek( p_sys->p_que ) ) {
> +            /* Get a new picture */
> +            p_pic = decoder_NewPicture( p_dec );
> +
> +            if( p_pic )
> +            {
> +                GstBuffer* p_buf = GST_BUFFER_CAST(
> +                        gst_atomic_queue_pop( p_sys->p_que ) );
> +                GstVideoFrame frame;
> +
> +                if( likely( GST_BUFFER_PTS_IS_VALID( p_buf ) ) )
> +                {
> +                    p_pic->date = gst_util_uint64_scale(
> +                            GST_BUFFER_PTS( p_buf ), GST_MSECOND, GST_SECOND );
> +                }
> +
> +                if( unlikely( !gst_video_frame_map( &frame,
> +                                &p_sys->vinfo, p_buf, GST_MAP_READ ) ) )
> +                {
> +                    msg_Err( p_dec, "failed to map gst video frame" );
> +                    gst_buffer_unref( p_buf );
> +                    p_dec->b_error = true;
> +                    break;
> +
> +                }
> +                else
> +                {
> +                    gst_CopyPicture( p_pic, &frame );
> +                    gst_video_frame_unmap( &frame );
> +                }
> +
> +                gst_buffer_unref( p_buf );
> +            } else
> +                break;
> +        }
> +
> +    } while (0);
> +
> +done:
> +    block_Release( p_block );
> +    *pp_block = NULL;
> +    return p_pic;
> +}
> +
> +/* Close the decoder instance */
> +static void CloseDecoder( vlc_object_t *p_this )
> +{
> +    decoder_t *p_dec = ( decoder_t *)p_this;
> +    decoder_sys_t *p_sys = p_dec->p_sys;
> +
> +	if( p_sys == NULL )
> +		return;
> +
> +    if( p_sys->b_running )
> +    {
> +        GstMessage* p_msg;
> +        GstFlowReturn i_ret;
> +
> +        /* Send EOS to the pipeline */
> +        i_ret = gst_app_src_end_of_stream(
> +                GST_APP_SRC_CAST( p_sys->p_decode_src ) );
> +        msg_Dbg( p_dec, "app src eos: %s", gst_flow_get_name( i_ret ) );
> +
> +        /* and catch it on the bus */
> +        p_msg = gst_bus_timed_pop_filtered( p_sys->p_bus,
> +                2000000000ULL, GST_MESSAGE_EOS | GST_MESSAGE_ERROR );
> +
> +        if( p_msg )
> +        {
> +            switch ( GST_MESSAGE_TYPE( p_msg ) )
> +            {
> +                case GST_MESSAGE_ERROR:
> +                    {
> +                        gchar  *psz_debug;
> +                        GError *p_error;
> +
> +                        gst_message_parse_error ( p_msg, &p_error, &psz_debug );
> +                        g_free( psz_debug );
> +
> +                        msg_Err( p_dec, "Error from %s: %s",
> +                                GST_ELEMENT_NAME( GST_MESSAGE_SRC( p_msg ) ),
> +                                p_error->message );
> +                        g_error_free( p_error );
> +                    }
> +                    break;
> +
> +                case GST_MESSAGE_EOS:
> +                    msg_Dbg( p_dec, "got eos" );
> +                    break;
> +
> +                default:
> +                    break;
> +            }
> +
> +            gst_message_unref( p_msg );
> +        }
> +        else
> +        {
> +            msg_Warn( p_dec, "failed to get message" );
> +        }
> +    }
> +
> +    /* Remove any left-over buffers from the queue */
> +    if( p_sys->p_que )
> +    {
> +        GstBuffer* p_buf;
> +        while( ( p_buf = gst_atomic_queue_pop( p_sys->p_que ) ) )
> +            gst_buffer_unref( p_buf );
> +        gst_atomic_queue_unref( p_sys->p_que );
> +    }
> +
> +    if( p_sys->b_running )
> +    {
> +        p_sys->b_running = false;
> +        gst_element_set_state ( p_sys->p_decoder, GST_STATE_NULL );
> +    }
> +
> +    if( p_sys->p_bus )
> +        gst_object_unref( p_sys->p_bus );
> +    if( p_sys->p_decode_src )
> +        gst_object_unref( p_sys->p_decode_src );
> +    if( p_sys->p_decode_in )
> +        gst_object_unref( p_sys->p_decode_in );
> +    if( p_sys->p_decode_out )
> +        gst_object_unref( p_sys->p_decode_out );
> +    if( p_sys->p_decoder )
> +        gst_object_unref( p_sys->p_decoder);
> +
> +    vlc_sem_destroy( &p_sys->sem_mt );
> +    free( p_sys );
> +    p_dec->p_sys = NULL;
> +}

Thanks!




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